Fertilizer.



UNITED STATES PATENT OFFICE.

THOMAS LEOPOLD WILLSON AND MAXIMILIAN MATTHEUS HAFF, OF OTTAWA ONTARIO, CANADA, ASSIGNORS, BY DIRECT AND MESNE .ASSIGNMENTS, TO SOUTHERN INVESTMENT CO. OF CANADA L'IIl, OF MDNTREAL, CANADA, A

CORPORATION OF CANADAf Specification of Letters Patent.

FERTILIZER.

Patented Sept. 25 1914;.

No Drawing. Original application filed July 10, 1912, Serial No. 708,548. Divided and. this application filed August 17, 1912. Serial No. 715,570.

To all whom it may concern Be it known that we, THOMAS L oPoLD "Wnmson and lVIAXIMILIAN Marrnnos I'IAFI, both of the city of Ottawa, Province of. Ontario, Dominion of Canada, have invented certain new and useful Improvements in Fertilizers, and do hereby declare the following to be a full, clear, and exact description of the same.

This invention relates to an improved fertilizer produced by a novel method of drying monocalcic phosphate and the like, applicable particularly to such phosphates as contain an excess of acid or are prepared from natural phosphate rock by the addition of phosphoric acid, and the objects are to produce a relatively dry and powdered fertilizer from monocalcic phosphate without affecting its relative solubility. Ordinary superphosphate contains from 14; to 16 per cent of phosphoric acid (P 0 and is in a comparatively dry state and suitable for use as a fertilizer. It contains monocalcium phosphate. It is prepared usually by the addition of sulfuric acid to a natural phosphate rock. To obtain calcium phosphate fertilizers having a higher percentage of available phosphoric acid, it is the practice to add phosphoric acid itself to natural phosphate rocks, to produce double superphosphate. The compounds produced contain from 20 to' per cent of phosphoric acid (P 0 but are in a more or less moist or damp condition and unsuitable for handling as a fertilizer, the degree of moisture varying with the amount of free phosphoric acid (P 0 It is not practicable to use ordinary drying methods with this highly concentrated compound for thereason that the costof such operations would be far in excess of the added value given by drying to the compound as a fertilizer.

According to the present invention, ammonia, preferably in the form of dry gas, is

introduced into the damp or pasty mass of double superphosphate containing monocalcic phosphate. This phosphate may be produced by treating natural phosphate rock with an aqueous solution of phosphoric acid; which may be the commercial form of liquid phosphoric acid. The function of the ammonia istwo-fold. In the first place it combines with the monocalcic phosphate to produce an ammonium calcium phosphate compound as hereinafter described, thereby increasing the fertilizing properties of the compound; and imt he second place the heat liberated by its reaction with the monocalcic phosphate 1s suiiicient'to dry the mass and bined moisture in the mass to be expelled,

thereby producing a commercially dry salt more adaptable for use as a fertilizer than the original moist ,or damp monocalcic phosphate. In addition to this a desirable quantity of nitrogen is introduced into the compound which increases its fertilizing value. The ammonium compound produced does not injuriously affect the availability of the phosphoric acid, as after treatment the P 0 of the fertilizer will still be found to be soluble in the standard ammonium citrate solution.

The compound ammonium monocalcic phosphate produced appears to be new.

From the nature of its constituents it forms a very valuable fertilizer. In physical form it is white, dry and crystalline. On heating,

ammonia is liberated.

What we claim is 2- 1. As a new article of manufacture, a substantially dry fertilizer composition con taining monocalcium ammonium phosphate and a little ammonium phosphate and containing no free acid. I

2. *As a new article of manufacture, a dry fertilizef containin an ammonium calcium In Witness whereof We have herenntq set phosphate, such p ospha'te containing at our hands in the presence of two Witnesses. least sufliclent ammonia to correspond to the THOMAS 'LEOPOLI) WILLSON. formula, Ca(NH )H (PO v MAXIMILIAN MAT'IIIEUS HAFF.

5 3. As a new fertilizer, a double superphos- Witnesses:

phate containing a substantial amount of RUSSELL S.SMART,

combined ammonia. PEARLE M. GANOU. 

